earthkit.meteo.thermo.fieldlist.wet_bulb_temperature_from_dewpoint

earthkit.meteo.thermo.fieldlist.wet_bulb_temperature_from_dewpoint(t, td, p=None, ept_method='ifs', t_method='bisect')

Compute the pseudo adiabatic wet bulb temperature from dewpoint.

Parameters:

• t (FieldList|Field) – Temperature (K).

• td (FieldList|Field) – Dewpoint (K).

• p (FieldList|Field|Iterable[float]|float|None) – Pressure (Pa). If None, inferred from the field metadata of t. Otherwise, if t is a FieldList p must be a FieldList or an array-like of the same length as t. If t is a Field, p must be a single Field or a float.

• ept_method (str, optional) – Specifies the computation method for the equivalent potential temperature. The possible values are: “ifs”, “bolton35”, “bolton39”. (See ept_from_dewpoint() for details.)

• t_method (str, optional) –

  Specifies the method to find the temperature along the moist adiabat defined by the equivalent potential temperature. The possible values are as follows:

  • ”bisect”: temperature_on_moist_adiabat() with t_method = “bisect” is used

  • ”newton”: temperature_on_moist_adiabat() with t_method = “newton” is used

Returns:

Wet bulb temperature (K). For values where the computation cannot be carried out nan is returned. The result has the same type as the input t and td (FieldList or Field).

Return type:

FieldList|Field

The computation is based on Normand’s rule [Wallace2006] (Chapter 3.5.6):

• first the equivalent potential temperature is computed with the given ept_method (using ept_from_dewpoint()). This defines the moist adiabat.

• then the wet bulb potential temperature is determined as the temperature at pressure p on the moist adiabat with the given t_method.